With the stroke of two pens, President Obama and Russian President Dmitri Medvedev signed a new nuclear disarmament treaty in Prague today, replacing the Strategic Arms Reduction Treaty (START) that expired Dec. 5.

"This ceremony is a testament to the truth that old adversaries can forge new partnerships," President Obama said today from the Spanish Hall at Prague's presidential castle.

The United States and Russia -- the world's two nuclear superpowers -- are pledging to reduce their nuclear arms by a third, making the historic agreement the first of its kind in two decades. The setting -- signing the treaty in Prague -- served as a symbolic gesture as it was this city where just over a year ago Obama spoke about his vision of a de-nuclearized world.

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Obama, Medvedev Sign Arms Reduction Treaty

The treaty requires both countries to reduce their nuclear arsenals from 2,200 deployed warheads for each country to 1,550 over seven years, a 30 percent reduction from the last treaty. And they'll reduce their long-range missiles and launchers to 700 for each country as well.

Obama this morning was welcomed to Prague with pomp and celebrations. Prior to the treaty signing, Obama and Medvedev held a long meeting to discuss Iran and the situation in Kyrgyzstan, where clashes between the government and protestors Wednesday left numerous dead.

At the signing, Secretary of State Hillary Clinton entered first, looked up at the ornate room and could be seen saying "Wow."

After they signed the treaty, Obama and Medvedev looked at each other, shrugged and then laughed.

Today's signing comes just days after the White House announced the administration's new nuclear strategy, calling for the elimination of nuclear arms testing and development of new nuclear weapons. In what has perhaps been the most controversial point of the new policy is the United States' commitment to not use nuclear weapons against any country that has signed and is abiding by the Nuclear Non-Proliferation Treaty, even if they attack the United States with chemical or biological weapons.

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June 18, 1979: SALT II

Focus on Iran

Critics say both the new policy and the U.S.-Russia arms agreement sends the wrong message to Iran, even as Obama administration officials argue that it puts more pressure on Iran to stop its pursuit of nuclear weapons.

The defiant Islamic state was high on Obama's priority list during his trip and meetings with state leaders. Both Obama and Medvedev pledged today to crack down on Iran with sanctions if it continues to advance its uranium enrichment program and pursue nuclear weapons.

"The United States and Russia are part of a coalition of nations insisting that the Islamic Republic of Iran face consequences, because they have continually failed to meet their obligations," Obama said. "We are working together at the UN Security Council to pass strong sanctions on Iran. And we will not tolerate actions that flout the NPT, risk an arms race in a vital region, and threaten the credibility of the international community and our collective security."

After the press conference, Russian deputy foreign minister Sergei Ryabkov said if sanctions were to be placed on Iran, they would have to be carefully considered and highly targeted.

"A total embargo on deliveries of refined oil products to Iran would mean a slap, a blow, a huge shock for the whole society. These types of things that shock the fundaments of a society are something that we definitely are not prepared to consider," Ryabkov told reporters.

White House officials countered that people talk about their red lines and bottom lines in all negotiations, and these discussions are no different.

"President Medvedev made publicly clear that he does not support sanctions that will lead to economic hardship for the Iranian people that would foment economic chaos or would lead to regime change," Michael McFaul, special assistant to the president and senior director for Russian Affairs, said today. "We actually agree with him on that."

U.S. officials agreed with the Russians that they want to use sanctions as a tool to change Iranian behavior. They refused to set more of a deadline for sanctions other than to say "in the broader context of spring."

Raw Nerves

Negotiators from the two countries have been working intensely on this issue since a year ago when Presidents Obama and Medvedev met, but it has not always been an easy process -- deadlines have been missed, negotiations at points have been difficult.

Medvedev once described the negotiations seeming like "Mission Impossible," yet today he touted that the agreement was a "win-win" situation.

Still, important differences remain. Russia continues to claim that the new treaty establishes an "inextricable connection" with missile defense, while the White House says they are wrong and argues the opposite.

At the press conference following the formal treaty signing today Obama said that plans for U.S. missile defense are not intended to change the "strategic balance" with Russia, but are instead aimed at "protecting the American people" from potentially new attacks from missiles launched from third countries.

"We recognize however that Russia has a significant interest in this issue," Obama said. "And what we've committed to doing is engaging in a significant discussion not only bilaterally but also having discussions with our European allies and others about a framework in which we can potentially cooperate on issues of missile defense in a way that preserves U.S. national security interests, preserves Russia's national security interests and allows us to guard against a rough missile from any source."

The president did add that he will not do anything that "endangers or limits" his ability to protect the American people.

"We also want to be clear that the approach that we have taken in no way is intended to change the strategic balance between the U.S. and Russia," he said.

The president said that discussions will continue to move forward, as part of which Medvedev will visit the United States this summer.

Medvedev said "at present' the language within the treaty signed "satisfies both parties" but indicated that he still hoped a compromise on this issue could be reached between the two countries.

Obama also faces resistance from some members of the U.S. Senate, who have to ratify the treaty. The agreement requires the signature of 67 senators to be ratified, which means Obama will need bipartisan support. But some Republicans argue that the agreement endangers and restricts the U.S. missile defense program. Others say the idea of a world free of nuclear arms -- a vision that the president has spoken about repeatedly since he took office -- is simply utopian.

The White House says they will begin working with the Senate to ratify this treaty immediately, with the expectation that it will be ratified this year.

"We will spend a lot of time, and our team will spend a lot of time meeting with individual senators and individual senator's staffs over the next many months to make this happen," White House press secretary Robert Gibbs told reporters.

He said earlier, "it's the president's hope and expectation the Senate will ratify this, this year."

Starting today, administration officials will begin briefing members of the Senate on the specifics of the treaty and the White House emphasized that prior arms control treaties have been ratified with huge bipartisan majorities.

Obama expressed confidence that ratification would be achieved by both countries.

"I am actually quite confident that Democrats and Republicans in the United States Senate having reviewed this will see that the United States has preserved its core national security interests, that it is maintaining a safe and secure and effective nuclear deterrent but that we are beginning to once again move forward leaving Cold War behind to address new challenges in new ways," he said.

In Russia also, the treaty needs to be ratified by the Duma, the country's parliament.

Ryabkov told reporters that they "would not hold the Duma hostage" and hope to have ratification by the U.S. midterm elections in November.

Obama Meets With European Leaders

Obama went from guest to host this evening in Prague. The president met with 11 leaders from Central and Eastern European for dinner at the ambassador's residence.

White House officials were adamant in rejecting the notion that the dinner was to reassure the Central Europeans that the warming of relations between the United States and Russia will not come at their expense.

"We have been clear cut from day one, from April 1, that as we advance our interest with Russia in seeking mutual cooperation, we're not going to link that to other places as a quid pro quo," McFaul, the president's special assistant, said. "That is simply not a game that we're going to play."

Administration officials said they believe a more substantive relationship with Russia is good for security in this region of the world.

"It's not a zero-sum game. It actually can be beneficial to both," McFaul said.

On the agenda at the meeting were wide-ranging issues including the global economy, European security and Afghanistan. Medvedev was not present at the meeting.

As for the unrest in Kyrgyzstan, the White House condemned the violence.

"We urge that calm be restored to Bishkek and other affected areas in a manner consistent with democratic principles and with respect for human rights," White House spokesman Gibbs said today in a statement. "We deplore the use of deadly force by some of the security services against the demonstrators and by some demonstrators and continue to be concerned by ongoing looting and disorder."